Stroke is a leading cause of death and disability in industrialized nations. Nearly 500,000 people in the United States suffer from stroke syndromes annually, at a cost of $23 billion. Strokes are caused primarily by an abrupt interruption of blood flow to a portion of the brain, due to arterial blockage. A less common cause of stroke is hemorrhaging due to a ruptured cerebral aneurysm.
Since strokes affect only one side of the brain, symptoms typically involve only one side of the body. Common symptoms include muscle weakness, numbness, paralysis, vision problems, loss of balance, loss of coordination, and speech impairment. These symptoms are often subjective, and often not easily discernable by the user. Furthermore, symptoms of stroke are rarely painful, unlike those in a heart attack. Therefore, people suffering from stroke are often not aggressive and inherently reluctant in seeking medical attention.
However, prompt medical attention is crucial for implementing treatment modalities that can dramatically minimize the long-term impact of the stroke for the user. One such therapy is the use of thrombolytic agents (“clot busters”) to restore blood flow to the ischemic zone. But, the effectiveness of this treatment drops off rapidly after the first hours following stroke. Moreover, after 3 hours of symptom onset, use of thrombolytics dramatically increases the risk of hemorrhaging, substantially worsening the outlook for the user.
Studies have indicated that only about 25% of stroke users arrive to a hospital in less than 2 hours, while approximately 60% arrive after 6 hours, well beyond the time window for effective treatment. The primary cause of this delay is the delay in the user deciding to seek medical attention. Clearly, public health care would be greatly benefited if more stroke users could present to a hospital in a more timely fashion.
There is therefore a great need for a user-implemented diagnostic tool to quickly, easily, and objectively diagnose symptoms related to the onset of stroke. Such a tool would help a user suffering a stroke to seek prompt medical attention.